Technical Field
The disclosure is related to liquid crystal display technology field, and more particular to a transflective liquid crystal panel and a liquid crystal display device having the transflective liquid crystal panel.
Related Art
Liquid crystal displays (abbreviated as LCD) with its excellent performance and mature technology currently have become mainstream products on the market. Liquid crystal panels are the key components of liquid crystal displays. Liquid crystal panels are mainly formed by color filter substrates and array substrates through cell assembly. The liquid crystal is filled between the color filter substrate and the array substrate to form a liquid crystal cell. Types of LCD panels can be divided as transmissive type, reflective type and transflective type according to the type of the light source.
The transmissive type LCD panel adopts a backlight as the light source. The backlight is disposed on the rear side of the liquid crystal panel. The pixel electrodes on the array substrate are transparent, and are used as a transmissive region for facilitating the light from the backlight going through the liquid crystal layer to display an image. The reflective type LCD panel adopts a front light source or an external light source as the light source. The array substrate adopts metal or other reflective electrodes using material having good reflective property as a reflective region for reflecting the front light source or the external light. The transflective type LCD panel is a combination of the transmissive type LCD panel and the reflective type LCD panel. The array substrate is provided with a transmissive region and a reflective region. The backlight and the front light source or the external light source are used simultaneously for display.
The transmissive type LCD panel has the advantage of display bright images in the dark environment. However the drawback is the transmissive light is a small portion of the light emitted from the backlight. The usage of the backlight is not high. In order to improve the display luminance it needs to greatly improve the brightness of the backlight, and therefore the energy consumption is high. The advantage of the reflective type LCD panel is that the external light source may be used and the energy consumption is low. However the drawback is that the image cannot be displayed in the dark due to the dependence on the external light source. The transflective type LCD panel has the advantages of the transmissive type LCD panel and the reflective type LCD panel. Not only the bight image may be displayed in the dark for indoor use but also the panel may used outdoors. Therefore, the transflective type LCD panels are widely employed on the display device of the portable mobile electronic products, for example, mobile phones, digital cameras, pocket PCs or GPRS.
However, the drawback of the transflective type LCD panel is that the light from the transmissive region only passes through the liquid crystal layer once, and the light from the reflective region passes through the liquid crystal layer twice. Thus the light from the different light sources in the transflective type LCD device has different optical paths in the transmissive region and the reflective region such that the chromatic aberration is larger between transmissive region and the reflective region. This results in the color incongruity for the image displayed in the transflective type LCD device. In order to improve the color incongruity, currently the transflective type LCD panel usually adopts double cell gap such that the cell thickness of the liquid crystal cell in the corresponding reflective region is half of the cell thickness of the liquid crystal cell in the corresponding transmissive region to ensure the equivalence between the phase delay of the liquid crystal in the reflective region and the phase delay of the liquid crystal in the transmissive region (that is the phase delay of the light passing through these two region may match with each other). Thus the color incongruity between the reflective region and the transmissive region is ensured to be smaller and the color congruity is ensured. However, the cell gap existing among the liquid crystal cells of the transflective liquid crystal panel complicates the manufacture process, and makes it difficult to control the uniformity of the cell gap.